Pedestrian-vehicle impact events are unfortunate but known occurrences as are impact events between vehicles and non-pedestrian objects. Vehicle object impact mitigation systems are known that can identify the location and size of an object impacted by the vehicle. Where such systems are associated with the front of the vehicle it is the width and location of the impact object that helps the vehicle's impact mitigation system to determine which, if any, active restraints should be deployed. Such systems may cause the vehicle to react differently depending on whether the impact object is a pedestrian or whether it is a non-pedestrian object.
Under the former circumstance, the vehicle impact mitigation system identifies a pedestrian and actively responds to the impact event. Active responses may be both external and internal. External responses might include, but not be limited to, bumper-mounted and hood-mounted airbags and hood-lifting systems. Internal responses might include, but not be limited to, the activation of steering wheel, dashboard, and seat belt airbags or side curtains.
On the other hand, if the vehicle impact mitigation system determines that the objected impact is not a pedestrian then no external response is needed although one or more of the above-mentioned internal responses may still be mandated.
In practice, the detection of a pedestrian impact requires full sensor coverage of the front end of the vehicle to minimize the potential injury to the pedestrian, and allow other non-pedestrian objects to impact the vehicle with no system detection/reaction. One known method of accomplishing this is through the use of two pressure sensors at opposite ends of the vehicle front end connected by a sealed tube. However, this architecture is not the most cost effective because it requires a pressure sensor at each end of the tube.
Accordingly, there is a need for a simple, inexpensive device for sensing the severity, location, and width of an impact. This information may be integrated with other sensor outputs by a control system to provide an intelligent crash mitigation system.
As in so many areas of vehicle technology there is always room for improvement related to the protection of pedestrians in a pedestrian-vehicle impact event.